18873221 has 4 divisors (see below), whose sum is σ = 18887712. Its totient is φ = 18858732.

The previous prime is 18873199. The next prime is 18873227. The reversal of 18873221 is 12237881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18873221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18873227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5075 + ... + 7968.

It is an arithmetic number, because the mean of its divisors is an integer number (4721928).

Almost surely, 2^18873221 is an apocalyptic number.

It is an amenable number.

18873221 is a deficient number, since it is larger than the sum of its proper divisors (14491).

18873221 is a wasteful number, since it uses less digits than its factorization.

18873221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14490.

The product of its digits is 5376, while the sum is 32.

The square root of 18873221 is about 4344.3320545281. The cubic root of 18873221 is about 266.2453358672.

The spelling of 18873221 in words is "eighteen million, eight hundred seventy-three thousand, two hundred twenty-one".